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2. BP, BP Energy Outlook 2019, available online at www.bp.com/en/global/corporate/energy-economics/energy-outlook.html.
3. China FTA Network, “China-GCC FTA”, available online at http://fta.mofcom.gov.cn/topic/engcc.shtml.
4. Energy Information Administration, “World Shale Resource Assessments”, 24 September 2015, available online at www.eia.gov/analysis/studies/worldshalegas/.
5. Groningen Growth and Development Centre, University of Groningen, “Maddison Project Database 2018”, available online at www.rug.nl/ggdc/historicaldevelopment/maddison/releases/maddison-project-database-2018.